1. Field
This invention relates to the treadmill type of exerciser and particularly to an exerciser operated by one leg which sets a standard for the basic components of running--footspeed, vertical thrust, horizontal thrust and frequency.
2. Prior Art
The basic capabilities that determine a runners maximum speed include his footspeed at the instant his foot contacts the ground, the horizontal thrust of his foot against the ground, the vertical thrust of his foot against the ground, and the frequency with which his foot contacts the ground. All of these capabilities vary from one individual to another. To some extent, deficiency in one capability can be compensated for by proficiency in another capability. This explains why individuals with different proficiencies in a given capability can be equally good (or poor) runners. For example, one runner with a short stride and large frequency may be as fast as another runner using a long stride and smaller frequency.
It is important to understand that we are addressing independent capability, not the actual performance of a given component during running. For example, the muscle group in a runners legs that determine frequency may be more proficient than the muscle group that determines foot speed (indicating that the runners hip extensors are more developed than his hip flexors). Then the runner will not be able to reach his maximum value of frequency because he will be limited by his foot speed. All of the components are related and the net result (top running speed) tends to be determined by the weakest component.
To consider each of these components individually--
A runner can have great foot speed (frequency) when the foot is out of contact with the ground, but, if he has a limited range of motion in his "back kick" then he can have slow foot speed when the foot is making ground contact because his muscles may be preparing for the forward swing. For example, a runner can be "running in place" (be stationery) at which point his foot speed at ground contact is zero and still be pumping his knees up and down at great frequency. In order to benefit from fast footspeed, a runner must either be able to have sufficient flexibility so as to execute an exaggerated hip flexion or he must have sufficient lean so that his hip is not in the process of converting from extension to flexion at the instant of foot contact. The former runner who is fast tends to have a more willowy (flexible) build whereas the latter runner who is equally fast tends to be more powerfully built.
A runner may have great foot speed but a relatively low reaction time (stride frequency.) If he has good vertical thrust (the vertical force) with which his foot hits the ground, then he can compensate for lower stride frequency.
Horizontal thrust has a very important influence on acceleration. During a short race of, say, 60 yards, the runner is accelerating from start to finish. Beyond 60 yards, most all runners have reached their top speed and are deccelarating. Therefore, development of horizontal thrust is important to a sprinter both in order to enable him to accelerate as great as possible in the first stage of the race, and to have the endurance to maintain his top speed as long as possible in the last part of the race.
The foregoing four factors are all related to one instant of the sprinters stride--the instant of foot contact. There are two other components whose importance cannot be discussed in terms of how they are directly related to the sprinters speed, but they can be discussed in terms of how they influence the four components that are directly related to speed. These two components are knee lift and back kick. It is useful to consider these two components separately.
Increasing the knee lift obviously does not increase frequency. In fact, increasing knee lift decreases frequency. However, by extending the range of motion within which the hip extensors are operative, the leg gains greater momentum by increasing knee lift so that vertical thrust, horizontal thrust and foot speed can be greater.
Most good sprinters have a high back kick. It is not the fact of the back kick per se that contributes to the speed. The back kick is simply an indication that the sprinters leg is in that range of motion where the angular velocity of his leg is great rather than at the end of its swing so that he has fast foot speed at ground contact.
The building of muscle groups involved in sprinting has historically been addressed by a sprinter going out on the track and running. There are certain exercises that he does which are intended to improve the various components discussed in the foregoing paragraphs, some of which are performed on the track and others of which are performed in the exercise room. The former exercises include hopping, running up bleacher steps, "eggshell" running in place, running with exaggerated knee lift, running with exaggerated back kick. In the exercise room, the sprinter may perform situps, squats, lunges, etc. in an effort to build strength. Efforts to build frequency have been made by hanging onto cars, holding one end of a stretched rubber band. These techniques are helpful but they are not nearly as effective as the techniques associated with the present invention. One reason is that the exercises (including the act of sprinting) do not "isolate".
A number of these exercises are extended to improve the "reaction time" of the user. Reaction time (or maximum frequency capability of the users muscle group) is determine by the quantity and quality of the Fast Twitch component of muscle fiber. U.S. Pat. No. 4,728,100 discloses a device and method of use involving interruption of a light beam as a means of signalling reaction time to a user as his exercise is in practice.
By isolate is meant that a particular muscle group is the major one providing the force for the exercise. When an exercise is performed that isolates on a particular muscle group, the entire cardiovascular system of the body supports that muscle group so that stress is concentrated on the muscle group. In the act of sprinting, the cardiovascular system must support the whole body so the physiological factor that limits stress on any of the involved muscle groups is the condition of the cardiovascular system.
U.S. Pat. No. 4,456,248 discloses an apparatus and program that can be used to isolate on muscle groups important for sprinting. The exercises disclosed are especially useful for building strength that can reduce the chance of injury associated with sprinting. However, the use of this apparatus can not be totally relied upon because it does not develop coordination associated with the act of running nor does it develop neurological proficiency. Use of this apparatus in combination with exercises performed on the apparatus of the present invention would provide the optimum exercise program.
Treadmills have been used for many years. These devices are looped belts that are run at controlled speeds so that a person standing on the belt is forced to walk "in place" at a speed dependent on the speed of the belt. Means are provided to tilt the belt to simulate the situation where the user is "walking uphill". These apparatus are often equipped with devices to measure heart and respiration rate, etc. They are really intended for people requiring moderate carefully controlled exercise such as recovering heart patients, etc.
In the following paragraphs will be discussed a principle of exercise that is very important in training for the optiomum rate of development of strength and speed although it is a principle that is not widely known or at least appreciated in coaching and exercise circles.
The principle is best illustrated by a weight lifting program because weight lifting, contrary to sprinting, can be designed to incorporate very small well defined increases of exertion into the daily program.
In training for improvement of strength and speed, if an exercise is performed every day that is too close to maximum exertion, then the volume (number of sets) of exercise is limited, the athlete does not have sufficient recovery between exercise bouts, he is subject to stress related injury, and he eventually reaches a peak. He also suffers psychologically as he sees his recent gains evaporate. On the other hand, if his exertion is too far below his maximum capability, he will have a limited rate of strength increase. These maximum and minimum values of most desired exertions are rather close to one another and must be defined by the athlete himself. In weightlifting, the athlete can stay within his bounds simply because he can control to a fine degree the amount of weight on the bar. Sprinting is a different story, however, because an athlete has no way of knowing when he is exerting himself within the optimum range.
In weightlifting, he can bench press 300 lbs. in one workout, 302 in the next, 304 in the next, etc. In sprinting, he can not run a 100 yds in 10.5 in one session, 10.4 in the next 10.3 in the next. Yet gradual increase in intensity, starting from a comfortable level, is the most effective way to development.